2-Chloro-3-formylpyridine (2-chloronicotinaldehyde) was obtained by reduction of 2-chloro-3-cyanopyridine by Raney nickel and formic acid (3 1); this intermediate is inaccessible by the above N-oxidation route (peroxyacid oxidation of 3-formylpyridine yields pyridine-N-oxide 3-carboxylic acid). In the synthesis of the parent 1 from 2-chloro-3-formylpyridine, the yield was prejudiced by the formation
2-
氯-3-甲酰基
吡啶(2-
氯烟醛)由雷尼
镍和
甲酸(3 1)还原2-
氯-3-
氰基吡啶得到;该中间体无法通过上述 N-氧化途径获得(3-甲酰基
吡啶的过氧酸氧化产生
吡啶-N-氧化物 3-
羧酸)。在由 2-
氯-3-甲酰基
吡啶合成母体 1 时,收率受到吖嗪物质 11 的形成的影响。